Lawful interception is a critical component of any mobile network in most countries. For example, in the United States, the Federal Communications Commission has mandated Communications Assistance for Law Enforcement Act (CALEA) for this purpose. The main requirement for this would be that the data/VOIP sessions from a mobile station (MS) can be wiretapped by law enforcement without the knowledge of the MS/user that his data is being tapped.
Thus, a strong need exists for techniques for lawful interception in wireless networks.
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